The present invention relates generally to valves with a predetermined travel distance, and more particularly to a valve lift spacer for adjusting the travel distance of a valve member.
In one class of valves, a valve member""s travel distance is determined by a thickness of a valve lift spacer, through which the valve member moves. The valve lift spacer typically separates two valve body components, such as an upper seat component and a lower seat component in the case of a three way valve. In some instances, consistent valve performance can be sensitive to variations in valve travel distance. For instance, relatively small fast acting pressure switching valves in fuel injection applications sometimes require consistent travel distances from one valve to another in order to produce consistent performance from one fuel injector to another. If the travel distances vary too substantially from one valve to another, the response time of the same can exceed acceptable variances, causing unacceptable deviations in performance from one fuel injector to another. Another problem associated with valves relates to routing passages through the valve in an effective and efficient manner. Efficiency could relate to decreasing valve leakage, whereas effectiveness could relate to ensuring a particular flow characteristic through the valve.
The present invention is directed to this and other problems associated with valve lift spacers and valves using the same.
A valve lift spacer comprises a metallic plate with a side surface separating the top surface from a bottom surface. The top surface includes a planar portion oriented parallel to a planar portion of the bottom surface. A valve travel bore extends between the top surface and the bottom surface. At least one of a first valve passage and a second valve passage extends between the top surface and the bottom surface.
In another aspect, a collection of valve lift spacers includes a plurality of plates, each belonging to one of a plurality of thickness groups. Each of the plates has a circumferential side surface separating an at least partially planar top surface from an at least partially planer bottom surface. Each plate also includes a valve travel bore, a first valve passage and a second valve passage extending between the surface and the bottom surface.
In still another aspect, a valve includes a first seat component separated from a second seat component by a valve lift spacer. A valve member is moveable between contact with the first seat component and the second seat component. A first passage is closed to a third passage when the valve member is in contact with the first seat. A second passage is closed to the third passage when the valve member is in contact with the second seat. At least one of the first passage and the second passage includes a segment extending through the valve lift spacer.
In still another aspect, a method of constructing a valve includes a step of trapping a valve member between a first seat component and a second seat component. The first seat component is separated from the second seat component by a valve lift spacer. A portion of at least one of the first passage and the second passage is located through the valve lift spacer.
In still another aspect, of the present invention, a method of making a fluid passage in a metallic valve component with a predetermined flow characteristic includes a step of opening a passage between opposing surfaces of a metallic valve component at least in part by machining a hole through the component. The hole is enlarged at least in part by flowing an abrasive slurry through the hole. A flow characteristic of the passage is measured. The enlarging step is performed until the measured flow characteristic is about equal to a desired flow characteristic.